Some sleuthing by VideoCardz suggests we may be looking at a February launch date. The description of a Ryzen optimization session at GDC 2017 specifically refers to the CPU as "recently-launched" so this sparks rumors of a launch date before this event.
The GDC 2017 is scheduled February 27 - March 3, 2017 so there's a chance we may see the Ryzen launch before the end of next month. AMD promises Ryzen will get a "hard" launch with immediate retail availability so hopefully this isn't another capsaicin-type event.